The quality of a printed image depends largely on the resolution of the printer. Accordingly, there are ongoing efforts to improve the print resolution of printers. The print resolution strictly depends on the spacing of the printer addressable locations on the media substrate and the drop volume. The spacing between nozzles on the printhead need not be as small as the spacing between addressable locations on the media substrate. The nozzle that prints a dot at one addressable location can be spaced any distance away from the nozzle that prints the dot at the adjacent addressable location. Movement of the printhead relative to the media, or vice versa, or both, will allow the printhead to eject drops at every addressable location regardless of the spacing between the nozzles on the printhead. In the extreme case, the same nozzle can print adjacent drops with the appropriate relative movement between the printhead and the media.
Excess movement of the media with respect to the printhead will reduce print speeds. Multiple passes of a scanning printhead over a single swathe of the media, or multiple passes of the media past the printhead in the case of pagewidth printhead reduces the page per minute print rate.
Alternatively, the nozzles can be spaced along the media feed path or in the scan direction so that the addressable locations on the media are smaller than the physical spacing of adjacent nozzles. It will be appreciated that the spacing the nozzles over a large section of the paper path or scan direction is counter to compact design. Furthermore, the fabrication cost and time increases with the number of times the stepper or scanner needs to index along the wafer to expose each step of the photo lithographic pattern. Each time the photo-imaging device indexes, it needs to accurately re-align with the previously imaged area of the nozzle array.